It is standard for a small portable electronic device—cell phone, PDA, MP3 player—to be constructed as two rigid parts, one of which carries a sensitive subassembly, for instance a display, keypad, or keyboard. The two parts, typically termed the cover and the base, are permanently connected together and can be moved between a closed position in which they take up minimal volume and the sensitive subassembly of the base is covered and protected by the cover, and an open position in which they are spread apart and the subassembly is exposed and usable.
There are three basic systems, best illustrated by the cell phone: The flip style simply has the cover and base hinged together along one edge to open and close like a clam. This is seen in the Siemens CF62 pivot phone, where the inner face of the cover carries the display and that of the base the keypad.
The pivot style also has a cover and base that lie in respective parallel planes, but the cover is pivotal relative to the base about an axis passing normally centrally through the cover and base perpendicular to the planes. The cover and base are elongated in their planes so that, when open, they cross each other. Such a system is seen in the Siemens SK65 and is useful to expose a fairly large keyboard on the base, with the outer face of the cover carrying the display.
The third system is the slide type and has, like the pivot type, elongated cover and base parts of the same shape and lying in respective parallel planes, but here the cover slides in its plane relative to the base, lengthening the device when open. This is embodied in the Siemens SL65 cell phone where the base carries at one end a keypad and the outer face of the cover has the display.
In all three systems it is necessary to provide a pivot and/or guide mechanism that allows the cover and base to move between the open and closed end positions smoothly, and also that urges them into and positively retains them in their end positions. Thus if the phone is open half way or more, it will snap into the full-open position, and if closed more than half way will snap into the full-closed position. Systems for doing this can be seen in U.S. Pat. Nos. 5,661,797, 5,983,083, and 6,085,387 and in U.S. patent publications 2002/0198016 and 2004/0098833.
Most of these mechanisms are fairly complex and expensive to manufacture. Furthermore few are adapted for use in pivot devices and none are useful in slide devices.